1. Field of the Invention
The present invention relates generally to methods of making a read sensor for a magnetic head, and more particularly to methods of making a read sensor with use of a barrier structure when depositing materials.
2. Description of the Related Art
FIG. 1 is a cross-sectional illustration showing one conventional step in a method of making a read sensor, such as a giant magnetoresistive (GMR) read sensor, of a magnetic head. More particularly, FIG. 1 shows a cross-section of mask 104 formed over a plurality of read sensor layers 102. Mask 104 is typically kept in place for use in etching read sensor materials 102 around mask 104 and subsequently depositing additional materials around a central read sensor 114 formed underneath mask 104. These deposited layers may be, for example, metal layers such as hard bias and lead layers. Mask 104 is typically a bilayer mask which includes a top layer of photoresist and a bottom underlayer of polymethylglutarimide (PMGI), for example. Methods of making read sensors with use of such masks include but are not limited to those described in U.S. Pat. No. 5,018,037. As an alternative, in the cross-section of FIG. 1 no bottom underlayer of mask 104 remains. Mask 104 of FIG. 1 is supported by surrounding materials (not visible in the particular cross-section shown) and may be referred to as a “bridged mask” or a “bridge”. Such bridged masks 104 may be used to form read sensors with very narrow track widths, for example, track widths below 0.15 micrometers (μm).
When materials are sputter deposited, they are directed at various angles, for example, at different angles designated by arrows 106 and 110. Relatively low angles of deposition (e.g. the angle designed by arrow 110) cause some of the materials to form too far underneath mask 104. Such formation may cause the materials to make physical contact with deposited materials from the other side of read sensor 114. If the materials being deposited are metal materials, such as hard bias and lead layers, they may cause an electrical short over the top of read sensor 114. Also, material layers formed along each side of read sensor 114 undesirably tend to be asymmetrical with respect to one another. Furthermore, each material layer formed along each side of read sensor 114 tends to be imperfect and varies in distance from the center of read sensor 114 in directions in and out of the page.
Accordingly, what are needed are methods of making read sensors which eliminate or reduce the problems associated with conventional processes.